The aim of this research is to identify some petrified wood discovered in Loa Janan district of Kutai Kertanegara East Borneo, for anatomical feature in the cross section, the hardness and the specific gravity as well. It was hypothesized that the petrified woods which were discovered would be endemic hardwood species from East Borneo. Six specimens with different size were taken and grinded with different grit (16 to 60). A binocular microscope was used to observe pattern of pores, rays, including resin ducts. Digital balance and measuring glass was used to determine the specific gravity, while selector diamond was used to determine hardness. Reference identifying was used to identify the wood species or genus. Result showed that all specimens were macroscopically identified as Fossil of hardwood, they were characterized by the existence of growth ring, pores, and rays. Most solitary pores grouping filled with mineral deposits were apparent in all of fossil woods. The diversity of color line was probably based on its formed minerals. The hardness of specimens were between 3 to 6 mosh, and were based on the color. The specific gravity of specimens were between 1,715 g/ml to 6,050 g/ml. The Important thing, that based on identification result, the biggest petrified wood which discovered in Loa Janan district of Kutai Kertanegara is most likely species of cf.Leptospermum family Myrsinaceae.

Observation of the macroscopic structure included color, hardness and density, while microscopic observations were carried out through three sections, namely the Transverse, Tangential, and Radial sections, using Stereo Microscope NIKON SMZ 645 and Research Microscope Eclipse E400 (equipped with a Nikon camera). The counted cells were: Pores (diameter, height, number), Rays (height, width, number), and the percentage of cells. The hardness value was calculated by using a rock hardness tester, namely 'Diamond Selector II'. Meanwhile, specific gravity was calculated by using general calculation standard for specific gravity, namely the ratio of mass to volume. The results showed that microscopically the two samples of wood fossils found were hardwood fossils (broad leaf wood) whose species was not yet known, with the characteristics of mostly solitary pores, uniseriate rays with heterogeneous arrangement. Meanwhile, the macroscopic observations of wood fossils FKM1 showed dark brown, light brown and a mixture of red. The second FKM2 showed light brown, yellow and dark brown colors. The hardness both was 4 on the Mohs scale, while the density were 3.25 and 3.04, respectively.

Penelitan ini merupakan lanjutan dari penelitian sebelumnya mengenai kehilangan berat kayu kapur (Dryobalanops sp) yang diinokulasi menggunakan jamur pelapuk putih (Schizophyllum commune) dengan nilai kehilangan berat kayu sebesar 0,12%. Inokulasi jamur S.commune dilakukan terhadap sampel Kayu Kapur pada media PDA (Potato Dextrose Agar) dengan masa inkubasi selama 4 minggu, Pengujian nilai kerapatan kayu dan nilai kadar abu dilakukan sebelum dan sesudah inokulasi dengan masing-masing menggunakan standar DIN 32182 dan TAPPI T211 om-93. Hasil penelitian menunjukkan terjadinya perbedaan yang tidak signifikan pada penurunan nilai kerapatan kayu dan peningkatan nilai kadar abu dari kayu kapur yang diinfeksi oleh jamur S.commune pada masa inkubasi selama 4 minggu

The results showed that macroscopically the studied wood fossils had brick red, gray, yellow, brown, and black in the first sample (FKA), and the second sample (FKB) had white, gray, and light brown colors, which this color difference was probably due to the cells being mixed with other inorganic elements even though they were found in adjacent locations. Another observation of the macroscopic features of the two samples indicated that cells were still obviously visible as on normal wood, such as pores, rays, and axial intercellular canal. Based on the characteristics of AIC, it was found to have general features that were often found in several types of wood in the Dipterocarpaceae family. The results of measuring the hardness value, the two fossil samples have the same hardness value, namely 4 Mohs scale. For the meantime, the specific gravity of the FKA and FKB samples were 2.54 and 2.35, respectively.

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